Internal-combustion engine.



H. LEMP. tINTERNAL ooMBUsTroN ENGINE.

APPLICATION FILED JAN. 26, 1912.

lPatented Oct. 21, 1913.

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HERMANN LEMP, OF LYNN, MASSACHUSETTS, ASSIGNOR T0 GENERAL ELECTRIC COM-PANY, A CORPORATION OF NEW YORK.

INTERNAL-COMBUSTION ENGINE.

Specification of Letters Patent.

Patented Oct. 21, 1913.

Application filed January 26, 1912. Serial No. 673,543.

To all whom 2' 1f may concern.

Be it known that I. HERMANN Lune, a citizen of the United States,residing at Lynn, county of Essex, State of Massachusetts, have inventedcertain new and useful Improvements in Internal-Con'ibustion Engines, ofwhich the following is a specification.

The present invention relates to internal combustion engines of the typeutilizing heavy oil and in which the temperature of the Huid Within thecylinder due to compression is utilized to lire the charge. In such. anengine the fuel has to be introduced into the compressed air charge inthe cylinder at or about the time the crank reaches its inner deadcenter. Obviously the fuel pump pressure has to be superior to thecompression pressure. It has been the practice up to date in engines ofthis class to drive the fuel pump at a speed which is only a fractionalpart of that of the main engine shaft.

.To this end they are commonly driven by the cam or half-speed shaft.

I have discovered that superior results may be obtained if t-he fuelpump, instead of being driven at a reduced speed, is driven at a speedconsiderably greater than that of the engine shaft. To state the matterin another way, the pump instead of being arranged to deliver the fullcharge of fuel on a given stroke at full load delivers only a portion ofsaid charge, thereby requiring a number of strokes to deliver' the fullcharge. It will, therefore, be seen that my invention is based on theplan of supplying fuel to the engine in successive fractional amo mts.increasing the number of said fractional amounts or discharges as theload rises and decreasing them as it falls` The amount of fuel requiredto operate the engine at Ano load is substantially one-sixth of thatrequired to operate it at full load. I, therefore, so arrange the pumpthat its actuator revolves three times as fast as the. main engineshaft, or if itI be driven by the halfspeed cam .shaft at six times itsspeed. Under these conditions it Will take si X strokes of the pump atfull load and but one stroke at no load to fill the cavity immediatelypreceding the oil inlet valve. of the engine, the latter being'positively actuated by the am shaft in usual manner. The pump piston`works full stroke all the time and at each stroke will deliver fuel ornot depending upon the load conditions. To regulate the pump a speedgovernor driven by the engine is provided that raises its suction valvefrom the scat when no fuel is required and permits it to seat when fuelis required. In this sense my improved governing mechanisni operates onthe hit-or-miss plan, the unit of cut-off, however, instead of being thefull supply of fuel is as many fractions thereof as is determined by thespeed governor. Such an arrangement permits of the use of a small pumpof simple construction and insures close regulation at all times andespecially at intermediate loads which is a factor of the utmostimportance, especially when the enginedrives constant speed electricgenerators. Owing to the arrangement specified the governor can beconnected directly to the suction valve operating means thereby reducingthe load thereon to such a small value as to prevent lag under loadchanging conditions. As the load required to be moved by the governor isdecreased so also the size of the governor may be decreased and hencethe cost of the same. By actuating the suction valve directly from thegovernor instead of interconnecting it with the pump plunger or some artmoving coincidently therewith, I avoid complication, reduce the numberof parts and their necessary pivots and joints and also improve thegoverning by reducing friction.

I have referred above to a single ump in order to simplify thedescription, ut it is to be understood that as many pumps Will beprovided as there are cylinders to the engine, and that all of thesuction valves will be operated at the proper time or times by the speedgovernor.

In the accompanying drawing which illustrates one of the embodiments ofmy invention, Figure l is a diagrammatic view of an engine and myimproved pump mechanism; Fig. 2 is a sectional view of the pump; Fig. 3is a detailed sectional View of the injector and valve for admittingfuel to the engine; and Fig. 4 is a diagrammatic illus-tration of theaction of each pump.

l indicates an engine which may have one, two or more cylii'iders andpistons of usual construction, said pistons being connected to the crankshaft 2 in the usual Way. Mounted on the crank shaft is a beveled gear 3meshing with a similar gear l for driving the governor shaft 5. On theupper end of the shaft is a speed governor' G having a sliding collar 7whose position is changed by changes in speed of the engine, z. e.raised by an increase and lowered by a decrease in speed.

S indicates a governor lever having pins which engage the collar andtransmit motion from the collar to the lever.

9 indicates the governor rod for actuating the suction valv:A or valvesof the pump or pumps as will appear later.

Mounted on the main shaft is a gear 10 that meshes with a gear 11 shownin dotted lines. This latter gear is mounted ou a shaft 12 that carriesthe eccentric 1S. The speed relation between the main engine shaft 2 andthe eccentric carrying shaft 12 is such that the latter makes threerevolutions to one revolution of the former. Surrounding the eccentricis an eccentric strap having a rod 14 that is pivotally connected to thecross-head 15. To the cross-head are connected as many pump plungers 1Gas there are pumps. Each of these pumps has a cylinder 17. Thesecylinders may be formed in a unitary structure or may be separate asdesired and are located Within a fuel containing tank 18. Each pump isprovided with a suction valve 19 located at its lower end and adischarge valve 20 that is normally held against its seat by the coiledcompression spring 21. Communicating with each discharge valve is a pipeQ2 for conveying fuel from the pump to its corresponding enginecylinder.

Each suction valve is provided with a downwardly extending stem 23 thatprojects through a suitable stuffing box in the bottom of the tank.Located below each suction valve is an arm 24 best shown in dot-r tedlines, Fig. 2. These arms are provided with set-screws 25 by means vofwhich the throw or movement of the valves can be accurately adjusted.The arms are rigidly mounted on the pivot 2G that is supported bysuitable bearings at its end. Mounted on the pivot 26 is a lever 2-7 thefree end of which is connected tothe rod 9 leading to the governorlever.

The pump is so proportioned and arranged that if it is in constanteffective action, it will pump during one complete cycle of each enginecylinder (four stroke cycle) enough oil to run it under full loadconditions, the worlnliowever, being divided into as many strokes as thefuel required for running light is contained in the total amount of fuelrequired at full load. In the present illustration six working strokesof each pump plunger are required for each engine cylinder, when thelatter is working at full load. The relation of the speed governor andthe suction valves is such that they are operated simultaneously. Thatis to say, the speed governor either raises all of the valves or permitsthem to close.

'In Fig. 4 is illustrated diagrammatically the operation of a pump. Theshort vertical lines represent the effective pump strokes and thecircles non-effective pump strokes. That is to say, in the firstinstance the suction valve 19 is supposed to be closed and in the latterinstance, to be open. In the upper row in said figure, marked No Loadone short line is shown and five circles, indicating that for eachfiring stroke of an engine cylinder the pump plunger makes one effectiveand five ineffective strokes. In the second line is shown three shortvertical lines and three circles. This is the half load condition andmeans that the suction valve 19 is closed for three strokes of the pumpplunger and is open for three. ln the last line of said figure isillustrated the full load condition. Six short vertical lines are shownindicating that plunger is making six effective strokes for each firingstroke of the engine, the suction valves 19 being closed on all of thedownward strokes of the pum plunger.

For simplicity I have described only the action of one pump, but it isevident that all pumps operate in the same manner. For loads immediatethose specified the number of effective pump strokes for firing theengine will be changed.

In Fig. 3 is shown a casing 28 that is lo cated in the head of eachcylinder. This casing contains a needle valve 29 for admitting fuelunder compressed air pressure through the nozzle 30 to the cylinder ofthe engine. Surrounding the needle valve are fine meshed screens orother devices 31 to insure proper mixing of the fuel and' air. Betweenthe needle valve and the inner wall of the casing is a chamber or cavity32 to which fuel is admitted by the pipe 22 from the pump, it beingunderstood that as many of these casings and needle valves are -providedas there are engine cylinders. 33 indicates a passage for admittingcompressed air from a suitable tank, the latter being supplied by an aircompressor. This air should be under a pressure greater than that of thecompression pressure within the engine cylinder. The needle valve isoperated by a lever 34 and a cam 35 driven by a cam or half speed shaft86 in the manner commonly employed in engines of this class.

In the operation of my invention the pumps will have anything from oneto six effective piston strokes to each firing stroke of the enginedepending upon the position of the speed governor, as determined by theload conditions. The fuel from each pump is forced into the cavity orchamber 32 where it remains until the cam 35 reaches a predeterminedposition Whensaid cam accopias o! this patent may be obtained lor tuatesthe lever 34 which in turn raises the needle valve 29 and permitscompressed air from the storage tank to force it into the cylinder. Owinto the high compression pressure within t e cylinder the charge of fuelwhether it be due to one stroke or six of the pump, is immediately fireddue tothe high temperature of the compressed air or other gas within thecylinder.

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention together with theapparatus which I now consider to represent the best embodiment thereof;but I desire to have it understood that the apparatus shown is onlyillustrative, and that the invention can be carried out by other means.

' What I claim as new, and desire to secure by Letters Patent of theUnited States, is

i. An internal combustion engine in conv bination with a fuel pumpcapable of dis'- placing on each working stroke only a fractional partof the amount of fuel required by the engine at full load and arrangedt0 deliver one or more fractional fuel charges to the engine for eachfiring stroke of the latter, means for driving tlie pump, and agoverning means that determines whether the pump shall deliver one ormore of such fractional fuel charges for each firing stroke of theengine.

2. An internal combustion engine in combination with a pump forsupplying fuel thereto comprising a cylinder, a/plunger which is drivenby the engine at a speed greater than that. of said engine, said plungerdisplacing on each working stroke onlyk a fractional part of the fuelrequired by the engine at full load, a suction valve for the pump, and aspeed Agovernor driveii by theA engine which controls the seating ofsaid valve.

An internal combustion engine in combination 11th a fuel pump thereforcomprising a ylinder, a plunger, a means actuated by the engine forimparting to the plunger a plurality of strokes for each firing strokeof the engine, suction and discharge valves for the pump, a speedgovernor driven by the engine, and a means moved by the governor whichcontrols the action of` the suction valve, said means being independentin its movements of the plunger actuating means;

4. An internal combustion engine in combination with a pump forsupplying fuel thereto which is proportioned andarranged to deliver tothe engine at each pump stroke an amount of fuel substantially equal tothat required for minimum load operation, means for driving the pump atsuch speed that at maximum load the pump will deliver to the engine foreach firing stroke an amount of fuel corresponding to the load by asuccession of strokes, and a speed governor that causes the pump todeliver one or more fractional charges of fuel to the engine dependingupon the load.

5. An internal combustion engine in combination with a pump forsupplying fuel thereto by successive strokes for each firing `stroke ofthe engine, the amount of fuel delivered at each stroke beingsubstantially the amount required for minimum load conditions of theengine, engine dri-ven gearing for imparting to the pump plunger a nur.-ber of strokes in excess of thc number' of firing strokes of the engine,suction and discharge valves for the pump, and a speed governor actingon the suction valve in a manner to cause one or more of the pumpstrokes to b e effective in delivering fuel to the engine depending onthe load.

6. A multiple cylinder internal combustion engine, in combination with amultiple plunger pump for supplying fuel thereto by successive strokesfor each firin stroke of the engine, the amount of fuel elivered at eachplunger'stroke being substantially the amount required for minimum loadconditions on the engine, means driven by the engine for imparting tothe plungers a number of strokes in excess of the numberrofy firingstrokes of the engine, suction and discharge valves for each pumpplunger, means for movin all of the suction valves, and a governor oractuating said means.

7. An internal combustion engine having a fuel receiving chamber`opening into the cylinder, in combination with a pump for supplying tothe chamber on each working( stroke an amount of fuel substantiallyequal to that required for minimum load operation of theengine, meansforimparting t0 the pump plunger a plurality of strokes for each Iii-ingstroke of the engine, suction and discharge valves for the pump, a speedgovernor for opening and closing the suction valve as the load changesto cause the pump to deliver one or more fractional fuel charges to the,chamben and a valve which admits fuel to the engine cylinder from thechamber. i f A In Witness whereof, I have hereunto set my hand this 20thday of January, 1912. 'HERMANN LEMP.

lVitnesses z HELEN Onroim, BENJAMIN B. HULL.

ve cents each, by addressing the Commissioner at rannte. Washington, D.C.

